Focus on Cornea

Treatment options for RCE: surgery, lasers and more

When medical management fails, diamond burr treatment and excimer PTK provide alternatives.

By Amir A. Azari, MD, and Christopher J. Rapuano, MD

Recurrent corneal erosion (RCE) is a condition that results in episodic loss of surface epithelium leading to redness, tearing, pain and photophobia. First described more than a century ago,¹ approximately one-half of RCE cases occur in eyes with a history of traumatic corneal abrasion.²

The interval between the first occurrence of the erosion and the initial abrasion can vary from two days to 16 years.³ Common mechanisms of injury leading to RCE are usually mechanical in nature; they include fingernail injury, tree branch injury and paper cuts.⁴

One third of the cases of RCE are due to epithelium basement membrane disorders,² usually involving both eyes, but often only one eye is symptomatic. The most common disease in this category is epithelial basement membrane dystrophy (EBMD), but clinicians have also encountered other dystrophies that involve the anterior cornea such as lattice, Reis-Bücklers and granular. Some cases result from a combination of traumatic corneal abrasion and disorders of epithelial basement membrane.²

Treatment of RCE has evolved from medical management and manual debridement and stromal puncture to Nd:YAG laser ablation and phototherapeutic keratectomy (PTK) with the excimer laser for more severe disease. This article explores the diagnosis of RCE and the prognosis of varied treatment approaches.

SIGNS AND SYMPTOMS

Eye pain and related symptoms

Eye pain is the classic symptom of RCE. However, depending on the severity of the episode, symptoms range from very mild foreign-body sensation to severe, debilitating pain.

Along with the eye pain, patients often experience decreased vision, which may also vary — from mild if the erosion is small and peripheral to extreme if it is large and central. Depending on the size of the erosion, symptoms may last anywhere from just a few seconds to minutes to many days.

Classifications of erosions

Recurrent erosions can be classified into micro- and macroerosions. Microerosions occur more frequently, the epithelial defect is smaller, and they often heal by the time the patient presents to the ophthalmologist.

Macroerosions are large and heal more slowly and are often associated with more pain and photophobia.⁵ The symptoms are typically most pronounced upon awakening in the morning, perhaps because the loose corneal epithelium adheres to the underside of the eyelid overnight and subsequent shearing stress occurs upon awakening and opening the eyes.

Signs and history

Also, it is not uncommon for patients to awaken in the night with symptoms of erosion. The overnight erosions may be due to the saccadic movement of the eyes during the REM sleep.⁶

Because recurrent corneal findings of RCE can resolve rapidly, the ophthalmologist’s examination can miss them. However, a frank epithelial defect, loose epithelium, epithelial microcysts and map lines/fingerprints (reduplication of EBM) and epithelial irregularity with a characteristic “negative staining pattern” present in many cases (Figures 1 and 2).

Figure 1. Histopathological examination of the cornea demonstrates reduplication of the epithelial basement membrane in this hematoxylin and eosin preparation. Some areas exhibit separation of the epithelial basement membrane from the underlying Bowman’s layer leading to poor adhesion (arrow head).

Figure 2. Slit-lamp photograph of a patient with history of recurrent corneal erosion shows redundant basement membrane creating a thickened, multilayered epithelium along with numerous epithelial inclusion cysts is visible.

The pathology in most cases is located in the central cornea just below the pupillary axis.⁷ A history of traumatic corneal abrasion in the same eye, similar painful episodes in the past in either eye, family members with RCE and presence of map lines, fingerprints or microcysts in the cornea of either are also strongly suggestive of RCE.

PROGNOSIS

Impact on quality of life

Recurrent corneal erosions cause significant patient debilitation and often present a major challenge to both the patient and the ophthalmologist. First of all, because the signs often resolve by the time the patient sees the ophthalmologist, the correct diagnosis of RCE is often delayed.

Even once the correct diagnosis is made, the treatment often is not aggressive enough, so the patient remains symptomatic for weeks, months or even years. This can often discourage the patient and ophthalmologist.⁸

A discouraging and debilitating course

Patients often fear recurrence of the disease and feel it is out of their control. They describe the unpredictability of the painful episode and whether it will cause them to miss a family event or an important meeting at work as upsetting and demoralizing.

Left untreated, RCE may also lead to significant loss of vision. Complications following RCE include infectious keratitis, non-infectious anterior uveitis, stromal scarring and irregular astigmatism.⁷

MEDICAL MANAGEMENT OF RCE

Lubrication and topical agents

The goal of medical management is to treat active erosions and prevent future episodes. Adequate surface lubrication, often achieved with frequent use of artificial tear eyedrops/ointments, plays an important role. A healthy tear film helps prevent further mechanical trauma to the surface epithelium and allows for better healing.⁸

Doxycycline and mild topical corticosteroids, such as fluorometholone, can help improve tear film quality. These agents inhibit matrix metalloproteinase (MMP)-2 and MMP-9 (inflammatory markers the tear film of patients with RCE up-regulates), and they have been shown to be effective in treating RCE. In addition to inhibiting MMPs, doxycycline improves tear lipid by improving the meibomian gland function.^9,10

Hypertonic solutions and ointments

Regular use of hypertonic solutions and ointments, such as 5% sodium chloride, helps to decrease the number of episodes of RCE because they deturgess the edematous corneal epithelium, allowing for better adhesion between the surface epithelium and the underlying Bowman’s layer.⁸

Many physicians believe the single most important medical treatment for RCE is an ointment (either a mild antibiotic or lubricating or hypertonic ointment) at bedtime.

Antibiotics and bandage lenses

In cases presenting with an epithelial defect, topical antibiotics can help prevent corneal infection. Therapeutic bandage contact lenses can relieve symptoms and prevent further epithelial trauma from the eyelids while the surface epithelium heals.⁷ A high-water content, large-diameter contact lens is preferable.^11,12 The contact lens typically stays in the eye for at least six weeks, allowing the epithelium to grow and firmly attach to the underlying Bowman’s membrane. Patients often receive broad-spectrum antibiotic drops while contact lenses are in place.

SURGICAL MANAGEMENT

Although aggressive medical management succeeds in many patients, approximately half will experience recurrence of their symptoms^2,13 requiring surgical intervention, which includes epithelial debridement alone, epithelial debridement with diamond burr polishing of Bowman’s layer, stromal micropuncture and excimer laser phototherapeutic keratectomy (PTK).

Simple epithelial debridement

This technique removes all the loose, abnormal epithelium, followed with placement of a bandage soft contact lens. Patients use topical antibiotic drops while the epithelial defect is still present. However, simple epithelial debridement is no more effective than medical management alone.³

Debridement with diamond-burr polishing

Epithelial debridement with diamond-burr polishing of Bowman’s layer involves first removing the abnormal surface epithelium either with a blade or alcohol. A handheld, diamond burr is then applied to the underlying Bowman’s layer for 10-15 seconds removing adherent layers of abnormal epithelial basement membrane allowing for better adhesion between the surface epithelium and the underlying Bowman’s layer.⁸

Diamond burr after surface debridement results in significant reduction in RCE. The number of studies reporting the outcomes of diamond burr are limited, but the recurrence rate has been reported to be from zero to 26.7%.^14-16

Stromal micropuncture

In this approach, the ophthalmologist creates approximately 100-200 micropunctures by inserting the tip of a 25-27G needle, which can be bent at 90°, into the anterior corneal stroma in the involved area and the surrounding 1 mm. The stromal punctures should be approximately 10%-20% of the corneal thickness (approximately 100 μm).¹⁷

Authors have reported recurrence rates of zero to 40% following stromal puncture.^2,18,19 This procedure can be performed either after removal of the abnormal loose epithelium or through an intact epithelium, and is most useful for small peripheral lesions that recur in the same area that are typically trauma related.

One must use stromal micropuncture with caution in the central cornea because of its proclivity for scar formation and reduced BCVA. Stromal micropuncture is the treatment of choice in post-LASIK eyes because other procedures that involve epithelial debridement may move the flap.

Nd:YAG laser

In this approach, the Nd:YAG laser beam focuses on the epithelial basement membrane in rows approximately 0.20 to 0.25 mm apart. One can also perform this procedure either after the abnormal loose epithelium has been removed or through an intact epithelium. Nd:YAG laser creates subepithelial scars and strong adhesion between surface epithelium and the underlying Bowman’s layer.^20,21

Phototherapeutic keratectomy (PTK)

PTK uses an excimer laser to treat the Bowman’s layer, thus allowing for a better adhesion by creating strong bonds between the corneal epithelial basement membrane and the underlying Bowman’s layer.⁷

Excimer PTK involves first removing the epithelium with a blade or alcohol, and then applying the laser to the involved area at a depth of approximately 5-6 μm. This procedure has a high rate of success.

Hurdles to greater use of PTK are its high cost, availability of an excimer laser to the surgeons and the logistics of performing the surgery in a laser center.⁷ The recurrence rate after PTK has been reported to be in the range of zero to 42%.^15,22-24

CONCLUSION

RCE is often a debilitating corneal condition that results from acquired or hereditary conditions affecting the epithelial basement membrane. Medical management consists of a combination of lubrication, soft contact lens and anti-inflammatory agents. For more severe and recalcitrant disease, epithelial debridement with diamond burr, PTK and stromal micropuncture may be indicated. OM

REFERENCES

About the Authors
	Amir A. Azari, MD, (top) and Christopher J. Rapuano, MD, are with the Cornea Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia. Dr. Azari’s e-mail is amirazarimd@gmail.com